WO2006037581A1

WO2006037581A1 - Drive train for a motor vehicle comprising an electric machine

Info

Publication number: WO2006037581A1
Application number: PCT/EP2005/010615
Authority: WO
Inventors: Marcus Heller; Jens Ranneberg; Sven Rolle; Wolfgang Schwienbacher; Yehia Tadros
Original assignee: Daimlerchrysler Ag
Priority date: 2004-10-06
Filing date: 2005-10-01
Publication date: 2006-04-13
Also published as: DE102004048908A1; US20070284157A1

Abstract

The invention relates to a drive chain for a vehicle comprising a conversion bell which is arranged between an internal combustion engine and a gear, which is transversed by the drive shaft, and contains a coupling device and an electric machine provided with a converter which comprises at least one capacitor (9) and power electronics (29). According to the invention, the capacitor and the power electronics are arranged in a distributed manner in the radial direction about the external periphery of the electric machine between the stator of the electric machine and the conversion bell. The capacitor (9) and the power electronics (29) are in heat-conducting contact for cooling the stator of the electric machine.

Description

Powertrain for a vehicle with electric machine

The invention relates to a drive train for a Fahrze'ug according to the closer defined in the preamble of claim 1 and an electric machine for a vehicle according to the closer defined in the preamble of claim 6 Art.

A generic powertrain is described by the publication Y. Tadros et al; "Ring Shaped Motor - Integrated Electric Drive for Hybrid Electric Vehicles", 10th European Conference on Power Electronics and Applications, Toulouse, 2003. In this case, an electric machine is integrated in a converter bell between the combustion engine and the transmission, in addition to a conventional clutch Machine, which may be formed according to DE 102 07 486 Al, has an integrated power electronics, which is cooled together with the stator of the electric machine.

Due to the connection of the power electronics to the stator or to the cooling in the axial direction of the electric machine, however, this is relatively thick in the axial direction and requires a corresponding amount of space. Especially in hybrid driving, the space requirement of such short and thick electric machines are a real disadvantage.

DE 103 25 527 A1 describes an integration of the power electronics together with a DC link capacitor into the electrical machine, wherein different types of power electronics and capacitor are used depending on the design and size.

At least with smaller electric machines, however, there arises the problem that the power electronics are typically flat and not rounded. With decreasing size of the electric machine so the contact area between power electronics and stator and thus the cooling is deteriorated.

In addition, the heating of the electrical machine during commissioning also exposes the annular capacitor to very high levels of thermal stress. At least when used in thermally highly loaded electrical machines, such as those of a drive train, which must deliver highly dynamic power profiles, and which are often switched on and off, it comes to high loads of the capacitor due to thermal expansion, especially in the direction of the circumference. The so-called Schoopschicht on the capacitor, which serves for its electrical contact, can easily get (micro) cracks due to the load, whereby the capacitor is unusable. Further, the expansion of the capacitor, which is most likely to express itself as an extension in the direction of its circumference, may deteriorate or lose contact with the cooling of the stator. The thus no longer or only badly cooled condenser thus heats up even faster, which is still the contact further deteriorated. This can eventually lead to a failure of the capacitor, as this will be too hot.

In the special case of the drive train, the cooling of the electric machine typically takes place via the cooling circuit of the internal combustion engine. Thus, the passive cooling and heating of the electric machine by the depending on the load state of the engine different cool or warm cooling water for the thermal load on the power electronics and in particular of the capacitor, with the above-mentioned disadvantages plays a crucial role.

Furthermore, EP 1 418 660 A1 discloses an electrical machine in which each winding of the stator is assigned a unit with power electronics. These units are distributed on flat surfaces around the circumference of the stator and are cooled by cooling channels together with this. A fluid-cooled electric machine of similar construction is also known from DE 101 12 799 C1, in which cooling elements of the power electronics protrude into a channel surrounding the stator for the cooling fluid.

This raises the problem that an intermediate circuit capacitor still has to be arranged outside the electrical machine. However, because of the inductions inherent in the line elements for their connection, considerable problems arise here with occurring voltage peaks, which can very easily damage the components of the line electronics, and here in particular the semiconductor switching elements. It is therefore the object of the above-mentioned invention to avoid the disadvantages described and to provide a very compact electric motor, for sole use or integration into a drive train, which is very compact and can be safely operated even under high thermal cycling loads ,

According to the invention this object is achieved by a drive train with the features in the characterizing part of claim 1.

By integrating both the electrical machine in the converter bell and the power electronics and the capacitor in the electric machine, a very compact electric drive module can be achieved in the drive train. On the one hand, the common cooling of the stator, capacitor and power electronics plays a role, since this makes such a compact electric machine possible in the first place. On the other hand, above all, the arrangement of the power electronics and the capacitor in the radial direction about the stator or the cooling of the same plays a decisive role, since only in this way can an electrical machine which is sufficiently compact, in particular in its axial extent, be achieved.

The combined cooling of the stator, capacitor and power electronics allows excess heat to be dissipated very easily and efficiently, which largely avoids thermal stress for the integrated structure of stator, capacitor and power electronics. Furthermore, the effort with regard to a modification of the vehicle cooling circuit is minimized since only a single further component to be cooled, namely the integrated structure, is minimized Stator, capacitor and power electronics, must be cooled.

The drive train according to the invention thus makes it possible to change the additional drive by an electric machine without having to change essential parts of the conventional drive train for this purpose. This makes it very simple and efficient possible to realize a hybrid drive concept for a vehicle with an electric machine that can be used as a motor and generator without having to change the previously customary powertrain in terms of shape and size. The drive train according to the invention can thus be easily integrated in conventional vehicles, without the need for constructive modifications of the drive train and its recordings, etc.

According e.inericularly advantageous development of the drive train according to the invention, it is provided to form this according to the features in the characterizing part of claim 2.

The arrangement of the capacitor and the power electronics and the electronics for controlling the power electronics in the at least two layers one above the other, a very good utilization of the available space in the converter bell can be achieved. The individual layers can have different dimensions in the axial direction of the electric machine and are thus easily adapted to the slope of the usually in trapezoidal cross-section transducer bell. The layered structure also allows the power electronics, which must be cooled, are arranged in the layer facing the stator, while the overlying oblique uncooled space for cooling uncritical electronics can be used to control the power electronics.

Furthermore, the above-mentioned object of the invention is achieved by an electric machine having the features in the characterizing part of claim 6.

With such a construction, a very compact electrical machine, in particular in its axial extent, can be achieved. In addition, extremely short distances of the electrical lines, in particular between the capacitor and the power electronics can be realized in the inventive construction of the electric machine. The inductances inherent in the leads are thus minimized. An impairment of power electronic components by voltage spikes, which can occur during operation, can thus be largely prevented.

The at least partial interruptions in the extent of the capacitor running around the circumference of the electrical machine ensure that it works safely and reliably despite the inevitably occurring thermal loads. The capacitor disposed around the periphery of the electric machine will inevitably heat up during operation. Despite active cooling, thermally induced changes in its extent occur time and again. Due to the integration of the capacitor around the circumference of the electric machine or the stator of the same, it is mainly in the direction of the circumference of the capacitor, which may be formed in particular annular, to considerable thermally induced changes in length. These changes in length lead to strong material stresses, especially in the metallic materials, such as the Schoopschicht of the capacitor, since these are not comparable have high elasticity, such as the polymeric films of a film capacitor. This (micro) cracks arising in the metallic materials would make the capacitor useless. In the structure according to the invention, however, these problems are now avoided by the capacitor having a plurality of at least partial interruptions distributed around its circumference. These serve as a kind of "expansion joints", which help to prevent a deterioration of the capacitor by the thermally induced loads.

According to a particularly advantageous embodiment of the invention, the capacitor according to the features in the characterizing part of claim 8 is formed.

By interrupting the entire capacitor into a plurality of sub-elements, the ideal circumvention of the abovementioned disadvantages with respect to thermal stresses in the capacitor is achieved. The capacitor, which can be wound in a particularly favorable manner as a single film capacitor and then interrupted, then has only comparatively short lengths, so that the thermally induced change in length does not lead to a defect.

The individual sub-elements of the capacitor are contacted via the busbar.

According to a preferred embodiment of the invention according to any one of claims 11 or 12, the busbar can have length compensation elements of different design.

Thus, the busbar can be protected from damage by thermal expansions. By the arrangement The length compensation elements in the area of interruptions creates a sufficiently flexible in length and very well-working construction.

An alternative embodiment of the at least partial interruptions is described by the features in the characterizing part of claim 9.

In this embodiment of the invention, not the entire capacitor, but only the Schoopschicht must be interrupted. In the case of capacitors, the term Schoop layer is understood as meaning the layer forming the respective electrical pole. For wound film capacitors, e.g. the respective faces of the foils on each side are joined together by spraying liquid metal. After curing, this sprayed metal then forms the respective contact surface, the so-called Schoop layer. These Schoopschichten formed on the axial side surfaces of the capacitor are distributed to the circumference of the capacitor, several times each completely interrupted. Also arise as expansion joints, which comparable to the above already shown, caused by thermal expansion (micro) cracks in the Schoop layer and thus prevent the mechanical damage to the capacitor by the thermal load, in particular the highly dynamic thermal cycling load.

A very advantageous development of the electric machine according to the invention is given by the features in the characterizing part of claim 16.

The circulating clamping band always presses the capacitor or its subelements onto the stator or the cooling of the stator. If the preload is chosen to be sufficiently large, can thus be achieved even with appropriate heating and stretching of the capacitor always a reliable contact of the capacitor with the stator or the cooling of the stator. The permanent cooling of the capacitor under all circumstances of the operation is thus ensured.

A very advantageous and favorable development of the invention further results from the features in the characterizing part of claim 19.

The polygonal region in addition to the capacitor, which itself may also be polygonal or preferably ring-shaped, allows the components of the power electronics to be mounted on flat surfaces. Thus, a large-area contact with the stator or the cooling of the stator and thus a good cooling of the same can be ensured. Another advantage of the polygonal range is that a modular design can be achieved with similar modules of the power electronics. The adaptation to the size or performance of the electric machine is then done only by selecting the number of sections, e.g. 6-angular, 8-angular or 12-angular. The same modules of the power electronics can then be installed on the flat surfaces of the individual sections or at least some of the sections, regardless of the size of the electrical machine. As with any other type of modular design, there are advantages in terms of flexibility. Furthermore, this can increase the number of units of the same modules across different sized electrical machines, which in turn reduces the cost of such module.

Further advantageous embodiments of the invention will become apparent from the remaining dependent claims, as well as from the hereinafter Ausführungsbeispielen described with reference to the drawing.

Showing:

1 is a drive train with internal combustion engine,

Converter bell and gearbox; 2 shows a possible interconnection of power electronics and a capacitor; Fig. 3 shows another possible interconnection of

Power electronics and a capacitor; 4 shows a possible arrangement of a capacitor around the electric machine; Fig. 5 is a schematic representation of a possible

Structure of the capacitor; 6 shows a possible embodiment of the interruptions of a Schoopschicht of the capacitor. Fig. 7 shows an alternative possible embodiment of

Interruptions of a Schoopschicht of the

capacitor; Fig. 8 shows a possible embodiment of the interruptions of the capacitor; Fig. 9 shows a possible embodiment of a current-conducting

Busbar with length compensation elements; 10 shows a possible structure of an arrangement of

Power electronics and capacitor around an electric machine;

Fig. 11 shows a possible arrangement of power electronics modules to a smaller electric machine; Fig. 12 shows a possible arrangement of power electronics modules to a larger electric machine; and FIG. 13 shows a possible arrangement of the power electronics and of the capacitor around the electric machine in an axial sectional view. In Fig. 1, a section of a drive train 1 can be seen in a schematic plan view. This comprises in its essential part an internal combustion engine 2 and a transmission 3. In between a converter bell 4 is arranged, in which a drive shaft 5 for driving the transmission 3 through the internal combustion engine 2 extends. As is generally customary, a coupling device 6 for separating the connection between the internal combustion engine 2 and the transmission 3 is also arranged in the converter bell 4. In addition, an electric machine 7 is arranged in the converter bell 4. By means of this, the vehicle provided with the drive train 1 can be driven in its motor operation. In a regenerative operation, for example in Ver¬ delay case of the vehicle, the electric machine 7 can also generate electrical energy and in a suitable storage device, such as a battery and / or a Hoch¬ power capacitor (supercap), feed back. Typically, such a drive train 1 is used in a hybrid vehicle. However, the electric machine itself would also be suitable for other ticks, for example for driving a fuel cell vehicle.

As is known from the prior art, so-called integrated drives are tested for space and cost reasons, i. Such drives in which the required for the operation of the electric machine 7 inverter or power converters are integrated in this.

In Fig. 2, such a converter 8 is shown with reference to its circuit diagram. Essentially, this consists of the power electronics and a Kondenstor 9, the so-called DC link capacitor. The power electronics in turn consist in the core of semiconductor switches 10 and diodes 11. It includes several so-called bridge arms 12, which in the circuit according to FIG. 2 each one of the Motor¬ windings 13 respond. The switches 10 of the power electronics are in each case actuated via the so-called gate drive units GDU 14, of which only one is shown here by way of example. Together with a control unit 15, these GDUs 14 thus form the electronics for controlling the power electronics, in which case a sensor 16 is also indicated, which supplies the control unit with feedback from the area of the electric machine 7 or the motor windings 13. This structure is connected between the electric machine 7 and an electrical power source 17 for this. The energy source 17 can be, for example, a battery and / or a high-performance capacitor and / or a fuel cell.

In Fig. 3, a comparable structure can be seen. This can be used for example to control electric machines 7 with a larger power. The control of each of the motor windings 13 takes place here by two or more bridge branches 12 in order to cope with the corresponding higher to be switched power.

The entire converter 8 is independent of its electrical interconnection, as stated above, integrated into the electric machine 7. This results in considerable advantages in terms of space requirements, costs, wiring and Elektro¬ magnetic compatibility (EMC).

The restrictive space conditions require partially unconventionally shaped components. In order to integrate the capacitor 9 as compactly as possible into the electric machine 7, it can be designed as a condenser 9 of annular design, for example, as shown in FIG. The condenser 9 must be cooled to a high To allow current carrying capacity. It is therefore mounted circumferentially on the outer circumference of a cooled support 18, which carries on its inside the not shown Motor¬ windings 13 of the stator of the electric machine 7. The cooled carrier 18 represents both the cooling for the capacitor 9 and for the stator. However, the carrier 18 has a different thermal expansion behavior than the capacitor 9. In order to keep the capacitor always in direct contact with the carrier 18 and thus ensure its adequate cooling, this is biased by a clamping band 19 around its outer periphery on the carrier 18. In this case, the bias voltage is to be chosen sufficiently large that the capacitor 9 is always pressed onto the carrier 18 under all conceivable temperature conditions and the lengthwise extension of capacitor 9, carrier 18 and clamping band 19 dependent thereon.

However, since high temperature fluctuations inevitably occur in the electric machine 7, in particular when it is operated highly dynamically, the capacitor 9 would be subject to considerable temperature changes with the thermal expansions associated therewith, which are particularly in the direction of its greatest extent, ie in the direction of the circumference make noticeable, subject. In order to enable a good thermal connection with simultaneous compensation of manufacturing tolerances and thermal expansions, a layer of a permanently elastic, highly heat-conductive material, for example a so-called silpad, can be applied between the condenser 9 and the cooled surface of the support become. This also achieves an increase in the thermal cycle stability. Of course, the capacitor 9, as an alternative to the representations chosen here, could also be cooled on its outer circumference. However, the same is true here too.

In the typical structure of such capacitors 9 as film capacitors, as is schematically indicated in Fig. 5 in cross-section, the capacitor 9 may consist of a plurality of corresponding metallized film layers 20 which are slightly offset directly on the support 18 are wound one above the other. Each of the side edges of the capacitor 9 is then provided with a layer which interconnects electrically and mechanically in each case half of the films, the so-called Schoop layer 21. This Schoop layer 21 may for example consist of liquid aufge¬ injected and then cured metal. The electrical contacting of the capacitor 9 takes place via the Schoop layer 21, whereby one Schoop layer 21 is connected to the positive pole, the other to the negative pole of the power source 17.

If it now comes to a thermal cycling with the corresponding alternating expansions of the capacitor 9, the relatively elastic films 20 are more likely to take no damage. The far less elastic Schoopschichten 21, however, get (micro) cracks or hairline cracks due to the changing thermal expansion. To avoid this, it is provided according to an embodiment of the invention to provide the Schoopschichten 21 with a plurality of distributed around the circumference complete or continuous interruptions 22.

Such continuous radial interruptions 22 are indicated by way of example in FIG. This as an expansion joint functioning interruption 22 allows the capacitor 9 to respond to thermal AC voltages accordingly, without this or its Schoop layer 21 is destroyed. The continuous interruption 22 of the embodiment according to FIG. 6 subdivides the Schoop layer 21 of the capacitor 9 into a plurality of individual regions 21a, 21b,... Of the Schoop layer 21. However, since this simultaneously represents the electrical contacting of the capacitor 9, the individual regions 21a , 21b, ... via an electrically conductive busbar 23 with length compensation elements 24, which is not shown here, but which will be discussed in more detail later, are interconnected.

An alternative embodiment for this purpose is schematically indicated in FIG. The interruptions 22 shown there are only formed as partial interruptions 22, so that each part of the Schoop layer 21 is maintained in the radial direction. If, as indicated in FIG. 7, at least three of the partial interruptions 22 are respectively grouped accordingly, the shoop layer 21 assumes a meandering configuration in this area. Thus, a compensation of the cyclic expansions due to the thermal cycling can be done without the Schoop layer 21 must be completely interrupted.

FIG. 8 shows a further alternative embodiment of the interruptions 22. Contrary to the previous statements, in which only the Schoop layers 21 have exhibited the interruptions 22, here the entire capacitor 9 in sub-elements 9a, 9b, ... interrupted. The individual sub-elements 9a, 9b, ..., which, for example, by separating a wound as a ring capacitor 9th are available are applied analogously to those already carried out on the carrier 18 and tensioned by means of the clamping band 19 against this. The clamping band 19 and the already mentioned electrically conductive busbar 23, which of course is also necessary here, are more clearly visible in FIG. The strap 19 includes as the outermost layer, the busbar 23, which each has a single rail 23+, 23- for each electrical pole. The individual rails 23+, 23- are in each case connected to one of the Schoop layers 21 of the partial elements 9a, 9b,... Of the capacitor 9. If the individual rails 23+, 23-, as here above each other, further electrical insulation 25 is provided between them. Preferably, the clamping band 19 is formed of an electrically conductive material. However, this must then be electrically insulated from at least one pole of the capacitor 9. It has been shown that such a construction with an electrically conductive strap 19 has a positive effect on the inductive behavior and the EMC of the electrical machine (7) or its power electronics.

To compensate for the thermally indexed length changes in the busbar 23 also length compensation elements 24 are provided. In the embodiment shown here they protrude into the interruptions 22 between the sub-elements 9a, 9b,... Of the condenser 9. The length-compensating elements 24 thus have sections 26 which extend substantially in the radial direction of the electric machine 7. On their side facing away from the main surface of the busbar 23, the sections 26, radially offset from the busbar 23, ensure the electrical connection between the individual areas of the busbar 23. If it comes to itself typically above all in the circumferential direction of the busbar 23 expressing thermal Induced expansions, they are absorbed by an elastic deformation of the length compensation elements 24. By the length compensation elements 24, the tolerances and thermal expansion in the interruptions 22 between the Teileleτnenten 9 a, 9 b, ... of the capacitor 9 can be compensated in the radial direction.

The arrangement of the length compensation elements 24 in the interruptions ^' 22 between the sub-elements 9a, 9b, ... of the capacitor 9 or in alternative embodiments of the busbar 23 in the region of the interruptions 22 in the Schoop layer 21, the length compensation elements 24 and as expansion joints acting interruptions 22 coordinated so that permanently safe operation of the capacitor 9 is made possible. This arrangement also saves space and the busbar 23 can equalize the forces acting on the capacitor 9 or its sub-elements 9a, 9b, ... forces.

Due to the high degree of integration of the capacitor 9 and in particular of power electronics, however, an optionally required repair is difficult and slightly different versions of the electric machine 7 each have special components necessary. Thus, it is almost impossible to use identical parts over different versions, which would, however, lead to a reduction in costs. Furthermore, 14 new ways must be taken in the design of the arrangement of the semiconductor components of the power electronics (switch 10, diodes 11) together with the associated GDUs to optimally utilize the available space.

Therefore, the power electronics in the radial direction on the outside of the carrier 18, for example in the axial direction of electric machine 7 is arranged offset next to the capacitor 9, as can be seen in Fig. 10. The carrier 18 is designed in this area as a polygon 27 that has a plurality of preferably flat surfaces 28. At least some of the surfaces 28 of the polygon 27 are equipped with power electronics modules 29, - not all surfaces 28 must be equipped. Due to the planar design of the surfaces 28, the components of the power electronics (switch 10, diodes 11) ^{"over the} entire surface and are thus very well cooled by the cooling in the carrier 18.

The power electronics modules 29 can, for example

^■ a bridge branch 12, possibly including the GDU 14;

^■ three bridge branches 12 smaller power;

^■ a possibly over the surface 28 of the polygon 27 cooled current sensor;

^■ inductive components, such as chokes;

^■ electrical filter components, such as Y-capacitors or common mode chokes;

^■ Cooled connection points, such as terminals for AC or DC connections;

^■ printed circuit boards with control electronics or sensors;

^■ PCBs with bus couplers, such as for communication via CAN bus;

^■ DC-DC converters, so-called DC / DC converters, for feeding the 12V on-board network of the power electronics control or for the redundant supply of safety-relevant consumers;

^{■ Contain} connection elements 30 for the cooling in the carrier 18. By different placement variants of the surfaces 28 of the polygonal region 27 with different power electronics modules 29, various designs in a modular design can now be implemented quickly and easily.

For example, the placement may be done with a minimum number of power electronics modules 29, e.g. three for an electric machine 7 small power, as has been explained as interconnection in Fig. 2. The remaining surfaces 28 of the polygon 27 can then carry other, not directly necessary for the control of the electric machine 7 electronic modules or remain empty.

Alternatively, the assembly for an electric machine 7 greater power, for example, with twice the number of power electronics modules 29, so six pieces done. The power electronics modules 29 are then either connected in parallel or each bridge branch 12 is connected to one end of one of the motor windings 13, whereby so-called "open windings" are realized.

In all cases, the equipment with additional (power) electronics modules 29 low power is possible:

^■ To integrate, for example, another power converter, which can be used for example for an oil pump or to power external consumers via a kind of power outlet; and or

^{■ to} raise the battery voltage with modules 29, which change the topology accordingly, to a higher, possibly regulated level (boost), from which then the actual power electronics modules 29 are fed to the electric machine 7. The support 18, which is flowed through by a cooling medium and which cools the stator S as well as the power electronics and the capacitor 9, also runs around the stator S here. For supply and removal of the cooling medium, the terminals 30 are provided.

The carrier 18 has an annular and a polygonal region 27, which are arranged next to one another in the axial direction of the electric machine 7. The capacitor 9 and the power electronics in the form of the (power) electronic modules 29 already described are distributed in the radial direction around the circumference in the radial direction. The capacitor 9 to be recognized on the right in FIG. 10 has its circumference distributes some radial interruptions 22 of its Schoop layer 21, which are not visible in Fig. 14, however. The sub-elements 9a, 9b,... Of the condenser 9 are contacted via two juxtaposed parts 23+, 23- of the electrical busbar 23. The length compensation elements 24 of the busbar 23 extend with their sections 26 in the axial direction to the electric machine 7. They can simultane- ously in the area in which they approach the (power) electronics modules 29, an electrical contact to have this. The length of the connecting cables is thus further reduced.

In FIGS. 11 and 12, a schematically indicated electrical machine 7 can be seen in cross-section. In addition to a rotor R with the shaft 31, the construction of the stator S and the cooled carrier 18 is shown here as a part. As can be seen from the illustrations, can very easily be adapted to the diameter and thus typically the performance of the electric machine. 7 respectively. This is possible via polygons 27 of different diameters and different numbers of surfaces 28. For example, for a small diameter electric machine 7, a polygon 27 having six faces 28, a large diameter electric machine 7, a polygon 27 having eight or twelve faces 28 may be used. Even polygons 27 with other surface numbers are of course possible. As a result of the modular design of the power electronics, identical (power) electronic modules 29 for different designs and sizes of electric machines 7 can be used, with ideal cooling due to the flat contact surface, and thus cheaper (in large quantities).

The polygon 27 can be designed as a receptacle for the (power) electronics modules 29 separated from the stator and / or the carrier 18 for the capacitor. Alternatively, however, the stator may also be embodied in its outer contour as a polygon 27 or as a polygonal carrier 18 with additional cooling channels. The possibility of segmenting the stator remains unaffected. If the polygon 27 is separable from the stator, it can be equipped with the power electronics before mounting the stator. This allows the entire power electronics to be tested before the stator is mounted.

The carrier 18 is, as already mentioned several times, carried out cooled. He may have either self-contained cooling channels, or the surfaces 28 of the polygon 27 may limit the cooling channels. If, in such a structure, individual surfaces 28 of the polygon 27 are unused, blind elements for closing the unused openings in the cooling circuit of the carrier 18 are of course necessary. If the surfaces 28 are now formed together with the (power) electronic modules 29 as one component, one can influence the subsequent cooling of the (power) electronics modules 29 very easily. Thus, surfaces 28 having a high cooling requirement can be cooled more directly and more intensively by arranging structures for reducing the thermal contact resistance, for example in the form of cooling fins, etc., on the side of the surface to be cooled 28 facing the coolant. However, areas 28 with less need for intensive cooling will not have such structures. Typically, the more intensively cooled surfaces 28 are commonly used for the high power dissipation power electronic devices. The less intensively cooled surfaces 28 can be used for the indirect cooling of the components with a lower power loss density, eg sensor technology, control of the power electronics, etc. An adaptation of the structures on the side facing the coolant according to the expected loss power density is easily possible. Thus, structures can be saved in places with low cooling power required, which brings manufacturing advantages and a reduction of the flow resistance in the coolant flow with it.

In order to further increase the usability of common parts in the selection of the (power) electronic modules 29, the polygon 28 can also have surfaces 28 of different lengths, as shown in FIG. 10. Due to the different angular pitch of the polygon 27, for example, 6 sections over each 40 ° and 6 sections over 20 °, even with smaller electric machines 7 at least some areas 28 are reached which provide sufficient space for, for example, one of the bridge branches 12.

The cramped space conditions in the integration of the electric machine 7 in the converter bell 4 a possible ideal utilization of the existing given space must be achieved. One possibility of using space is shown in FIG. 13. Under the sloping space restriction 32 through the transducer bell 4 (not shown here), the flat portion of the power electronics, i. the ceramic substrate 33 with the bonded chips (switch 10 and diodes 11), positioned as far as possible under the slope and the associated electronics for driving and the GDU 14 in one or more axially to the electric machine 7 shortened and / or offset overlying layers 34th adapted to the slope 32. The layers 34 may also come to lie partially over the capacitor 9. This can lead to an increased length of the control lines due to lack of coverage of substrate and control electronics, but saves space.

All in all, due to the very compact integration and the immediate vicinity of capacitor 9 and (power) electronic modules 29, the length of the connecting lines in the structures shown here is kept short. The occurrence of inductively induced voltage peaks can thus be reduced to an absolute minimum.

Claims

claims

A drive train for a vehicle, wherein between a combustion engine and a transmission, a converter bell is arranged, through which the drive shaft extends, and in which a coupling device and an electrical machine, including at least one capacitor and power electronics comprehensive converter are integrated, characterized in that the capacitor (9) and the power electronics in the radial direction around the outer circumference of the electric machine (7) distributed between the stator (S) of the electric machine (7) and the converter bell (4) are arranged, wherein the capacitor (9) and the Power electronics are arranged in heat-conducting contact with the cooling of the stator (S) of the electric machine.

2. Drive train according to claim 1, characterized in that the capacitor (9) and the power electronics together with electronics for controlling the power electronics in at least two layers (34) are formed one above the other, wherein the layers (34) in the axial direction of the electric machine ( 7) have different dimensions and / or offset from one another.

3. Drive train according to claim 1 or 2, characterized in that the capacitor (9) on an annular region of the stator (S) or the cooling of the stator (S) is arranged.

4. Drive train according to claim 3, characterized in that the stator (S) or the cooling of the stator (S) in the axial direction of the electric machine (7) adjacent to the annular region lying polygonal region (27), wherein at least some the planar surfaces (28) of the polygonal region (27), the power electronics is arranged.

5. Drive train according to claim 3 or 4, characterized in that the polygonal region (27) has surfaces (28) of different edge length.

6. Electrical machine for a vehicle, in particular for integration into a drive train according to one of claims 1 to 5, wherein the electric machine is at least usable as traction motor, and wherein the control thereof by means of at least one capacitor and power electronics comprehensive converter, characterized in that the power electronics of the converter (8) are distributed in the radial direction around the outer circumference of the electrical machine (7) and the capacitor (9) extends in the radial direction around the outer circumference of the electric machine (7), wherein the capacitor (9) distributed over the circumference of the capacitor (9) has a plurality of at least partially interruptions (22).

7. Electrical machine according to claim 6, characterized in that the capacitor (9) and the power electronics with a cooling of the stator (S) of the electric machine (7) is in heat-conducting contact.

8. Electrical machine according to claim 6 or 7, characterized in that the entire capacitor (9) in a plurality of sub-elements (9a, 9b ,. ") is interrupted, wherein the sub-elements (9a, 9b, ...) via an electrically conductive Busbar (23) are contacted.

9. Electrical machine according to claim 6 or 7, characterized in that Schoopschichten (21) of the capacitor (9) are formed on the axial side surfaces and distributed around the circumference several times each with extending in the radial direction complete interruptions (22), wherein the individual regions (21a, 21b,...) of the Schoop layers (21) are contacted via an electrically conductive busbar (23).

10. Electrical machine according to claim 6 or 7, characterized in that Schoopschichten (21) of the capacitor (9) are formed on the axial side surfaces and to the. Circumference distributed several times partial interruptions (22) are provided, wherein at least three of the Partial interruptions (22) are grouped so that the Schoopschichten (21) assume a meander-shaped configuration in this area.

11. Electrical machine according to claim 8 or 9, characterized in that the busbar (23) length compensation elements (24) having substantially in the axial direction of the electric machine (7) extending portions (26) axially offset from the busbar (23 ) ensure the electrical connection of the individual areas of the Ver¬ (23).

12. Electrical machine according to claim 8 or 9, characterized in that the busbar (23) length compensation elements (24) with substantially in the radial direction of the electric machine (7) extending portions (26) which radially offset from the busbar (23 ) ensure the electrical connection of the individual areas of the busbar (23).

13. Electrical machine according to claim 12, characterized in that extend the length compensation elements (24) in the areas between the sub-elements (9a, 9b, ...).

14. Electrical machine according to claim 11, 12 or 13, characterized in that the length compensation elements (24) of the busbar (23) in the same areas of the capacitor (9) are arranged, as its at least partial interruptions (22).

15. Electrical machine according to one of claims 11 to 14, characterized in that 'the electrical contact between the busbar (23) and the power electronics in the region of the length compensation elements (24) is arranged.

16. Electrical machine according to one of claims 6 to 15, characterized in that the capacitor (9) by a circumferential clamping band (19) is held under prestress on the stator (S).

17. Electrical machine according to claim 16, characterized in that the clamping band (19) is formed from an electrically conductive material, wherein it is at least to one pole of the capacitor (9) electrically insulated.

18. Electrical machine according to one of claims 6 to 17, characterized in that the capacitor (9) on an annular region of the stator (S) or the cooling of the stator (S) is arranged.

19. Electrical machine according to one of claims 6 to 18, characterized in that the stator (S) or the cooling of the stator (S) in the axial direction of the electric machine (7) adjacent to the capacitor (9) lying polygonal region (27 ), wherein at least on some of the flat surfaces (28) of the polygonal region (27) Leistungs¬ electronics is arranged.

20. Electrical machine according to claim 19, characterized in that the polygonal region (27) has surfaces (28) of different edge length.

21. Electrical machine according to claim 19 or 20, characterized in that the number of surfaces (28) of the polygonal region (27) increases with increasing diameter of the electric machine (7).

22. Electrical machine according to claim 19, 20 or 21, characterized in that the side facing away from the power electronics side of the surfaces (28) of the polygonal region (27) is in contact with a cooling liquid.

23. Electrical machine according to claim 22, characterized in that the at least some of the surfaces in contact with the cooling liquid (28) have cooling fins for improving the heat transfer between surface (28) and cooling liquid, wherein configuration and / or presence of the cooling fins in dependence the power loss generated by the power electronics arranged on the respective surface (28) is predetermined.

24. Electrical machine according to one of claims 19 to 23, characterized in that the polygonal region (27) is detachably formed on the stator (S) of the electric machine (7).

25. Electrical machine according to one of claims 6 to 24, characterized that the capacitor (9) is wound directly onto the stator (S) or the cooling of the stator (S).